1. Field
Exemplary embodiments of the present invention relate to an apparatus and method for processing an image in a digital camera, and more particularly, to an apparatus and method for processing the intensity of an image taken by a digital camera.
2. Description of the Related Art
Digital cameras have been used in various fields, for example, general pictures and digital motion pictures. Digital cameras take images using photosensitive sensors made of a semiconductor material, and the photosensitive sensors are generally divided into two photosensitive sensors. The first sensor is a charge coupled device (CCD), and the second sensor is a CMOS image sensor or contact image sensor (CIS).
The two photosensitive sensors will be briefly described. A fabrication process of the CCD is more complicated than a fabrication process of the CIS, but the CCD has superior resolution to the CIS. Therefore, the CCD is more expensive than the CIS. However, digital cameras using the CCD are more frequently used to obtain high-quality images.
On the other hand, the digital cameras using the CIS achieve image quality compensation to a certain extent in a wide dynamic range.
Meanwhile, there is a Retinex technique that is a compensation technique for improving low luminance and image quality in the wide dynamic range.
In the Retinex technique, an image is compensated through a dynamic range compression process and a color restoration process. More specifically, in the Retinex technique, an image is compensated by modeling one image taken by a digital camera using scene (S), illumination (L), and reflectance (R). In the Retinex technique, a model of S=L*R is used. For reference, the scene can be captured by the digital camera, but the illumination and the reflectance cannot be directly measured by the digital camera. For this reason, in the Retinex technique, components L and R are extracted by performing a logarithmic operation on both sides of the model of S=L*R, and enhancement is performed on the extracted components L and R. By extracting and enhancing the components L and R, a wide dynamic range for improving low luminance may be achieved.
The related art uses a large quantity of hardware resources. A digital camera using the Retinex technique uses a low pass filter to obtain the illumination component, and many line memories are also used. In the Retinex technique, a line memory of 10 lines or more is used.
Additionally, in a digital camera using a technique other than the Retinex technique to improve the luminance of an image using the CIS, a bright area becomes brighter, and/or an original color is not maintained, and/or consecutive frames are not natural.